MIT engineer Alexander Rabinovich holds a
device he developed with Leslie Bromberg (left), Daniel Cohn
(right) and colleagues that could significantly reduce the
amount of smog-producing pollutants generated by cars.

MIT device could lead to near-term
environmental improvements for cars

A car that runs on vegetable oil?

MIT engineers and colleagues are perfecting a device that could
turn that foodstuff and various "biocrude" oils into fuel that
could reduce the nation's dependence on foreign oil and decrease
emissions of the greenhouse gas carbon dioxide. The same device
could also significantly reduce the amount of smog-producing
pollutants generated by vehicles running on traditional fuels.

All that from a contraption the researchers believe will be
relatively inexpensive--only a few percent of the cost of a car or
truck. They also believe that it could be introduced into present
vehicle technology with only minor modifications, and that it will
only need to be replaced a few times over the lifetime of a
vehicle.

Essentially the device, which is about the size of a large soup
can, works as an onboard "oil refinery." It converts a wide
variety of fuels into high-quality hydrogen-rich gas. Adding only
a small amount of such gas to the fossil fuel powering a car is
known to make possible a significant decrease in emissions of
pollutants like nitrogen oxides.

"This device might dramatically reduce air pollution from autos
and trucks without a major increase in costs and inconvenience,"
said Daniel R. Cohn, a senior research scientist at the MIT Plasma
Science and Fusion Center (PSFC). "The device has near-term
applications. No major advances are needed in internal combustion
engine design to incorporate it."

Dr. Cohn's colleagues on the work are PSFC principal research
engineer Leslie Bromberg, PSFC research engineer Alexander
Rabinovich, and Jeffrey E. Surma and Jud Virden at the Battelle
Pacific Northwest National Laboratory. The team will present a
paper on the work October 28 at the DOE Automotive Technology
Development Customers' Coordination Meeting.

The new device is a kind of electrical gas heater known as a
plasmatron. Fuel injected into the plasmatron is exposed to an arc
of electricity that turns the fuel and surrounding air into an
electrically charged gas, or plasma. The plasma accelerates
reaction rates allowing the production of hydrogen-rich gas in a
compact device--the plasmatron.

Plasmatrons have traditionally been used to produce hydrogen-rich
gas for industrial applications like metallurgical processing.
They are usually quite large--about the size of a car engine--and
require large amounts of electrical power. "We're the first to
develop a compact, low-power plasmatron," said Dr. Cohn. "To our
knowledge no-one has created one that's this small (you can hold
it in your hand) and that operates at low power (around one
kilowatt)."

In contrast, the new plasmatron works well with a variety of
fuels. "We've shown a very high degree of conversion (over 90
percent) of gasoline, diesel, and biocrude fuels into
hydrogen-rich gas," Dr. Cohn said.

Although in principle the plasmatron could process all of the fuel
for a vehicle, the researchers say that at present it's most
cost-effective to convert only a fraction of the fuel into
hydrogen-rich gas. That's because even though such gas increases
the efficiency of an engine, the plasmatron itself consumes
energy. "Processing a fraction of the fuel should prevent any
decrease in net fuel consumption efficiency, and may in some cases
improve net efficiency," Dr. Cohn said.

Pollution reduction is significant. For example, converting 25-50
percent of gasoline into hydrogen-rich gas "could reduce nitrogen
oxide levels by a factor of five to ten relative to operation
without hydrogen-rich gas," Dr. Cohn said. For natural gas, even
less fuel need be converted for similar pollution reductions.

Biocrude oils have their own environmental benefits. "Such oils
might be produced by fast-growing trees or other crops that absorb
carbon dioxide, compensating for the carbon dioxide produced by
combustion," explained Dr. Cohn.

The researchers are currently working to increase the efficiency
and yields of the plasmatron. They are also developing designs
that will give a longer lifetime for the electrodes.

In a parallel effort, they are conducting experiments on the
effects of hydrogen-rich gas on internal combustion engines. The
original experiments to this end that found significant benefits
to the use of such gas were conducted in the 70s. "We want to
reexamine engine performance with hydrogen using modern engines,"
Dr. Cohn said.

The new plasmatron grew out of work conducted over 15 years ago by
Dr. Rabinovich, who was then an engineer in the former Soviet
Union. Drs. Rabinovich, Cohn and Bromberg have written several
papers on this topic, and in 1995 received a patent on using the
plasmatron in internal combustion engines.

The work is supported by the DOE Office of Heavy Vehicle
Technologies. Dr. Cohn noted that "we'd been considering these
applications for some time, but it wasn't until we received this
DOE funding that we could really move forward to try to validate
our concepts for vehicular applications."

The world's smallest oil refinery sits in a first-floor lab at
MIT. Called a plasmatron, it looks a bit like a spark plug that
ate too much. And what an appetite it has! MIT researcher Daniel
Cohn has fed the plasmatron gasoline, diesel, even canola oil.
Eagerly swallowing anything that burns, the device lets go with a
belch of electricity that turns the fuel and surrounding air into
plasma, a hot collection of charged atoms and electrons. What
comes out is a hydrogen-rich gas that burns far more cleanly than
garden-variety gasoline.

Cohn and his colleagues are betting a version of their device
would work wonders on the family automobile. Tucked beneath the
driver's door, a soup-can-size plasmatron could siphon off a
fraction of the fuel traveling from the gas tank, refine it in
just a second, then send it to the engine. Together, the
charged-up gas and untreated fuel would burn so readily that the
engine would in turn run more efficiently, producing only a
fraction of the normal smog-causing pollutants. Best of all, the
microplasmatron works with ordinary gasoline — no fancy new fuels
required.

Engineers have known for years that adding hydrogen to fuel makes
an engine run cleaner. "The trick was figuring out how to produce
hydrogen quickly and compactly on board," Cohn says. He and his
researchers got the plasmatron idea from colleagues working in
metallurgy who mix hydrogen-rich gases with oxygen-rich compounds
to extract metals. In miniature form, the plasmatron would
function as a kind of super-carburetor.

The prototype plasmatron at MIT could convert about one-quarter of
a typical automobile's fuel into hydrogen. Enough, Cohn says, to
cut emission of smog-causing nitrogen oxides by 90 percent. Having
proven the plasmatron works in the lab, researchers now plan to
try it in a stationary engine. If they're successful, the device
could be cleaning up cars, trucks, and buses around the world in
less than a decade.

An MIT device that could drastically cut smog-producing emissions
from cars and other vehicles is a significant step closer to
moving from the lab to the road. The device, known as a
plasmatron, is expected to be inexpensive and readily compatible
with present engine technology.

Recently the plasmatron was installed in a commercial car engine
for the first time. It operated reliably over two weeks, and met
its inventors' expectations for reducing emissions of pollutants,
particularly nitrogen oxides (NOx). NOx emissions were reduced by
two orders of magnitude compared to the normal emissions of an
engine running on gasoline.

"This is a major milestone in showing the feasibility of a
plasma-boosted fuel reformer for reducing vehicle pollution," said
Daniel R. Cohn, head of the Plasma Technology Division at the
Plasma Science and Fusion Center (PSFC). Dr. Cohn will be
presenting the work November 18 at a meeting of the American
Physical Society.

Now that the researchers have successfully coupled the plasmatron
to an engine, the next step is to install the device in an actual
vehicle. "We're ready to take the show on the road," Dr. Cohn
said.

Dr. Cohn's colleagues on the current work are PSFC principal
research engineer Leslie Bromberg, PSFC research engineer
Alexander Rabinovich, PSFC visiting scientist Nikolai Alexeev, and
five engineers from Oak Ridge National Laboratory, where the
engine tests were conducted.

HOW IT WORKS

Essentially the plasmatron, which is about the size of a wine
bottle, works as an onboard "oil refinery." It converts a variety
of fuels into high-quality hydrogen-rich gas. Adding only a small
amount of such gas to the fossil fuel powering a car is known to
significantly decrease emissions of pollutants like NOx.

Fuel injected into the plasmatron is exposed to an electric
discharge that turns the fuel and surrounding air into an
electrically charged gas, or plasma. The plasma accelerates
reaction rates allowing the production of hydrogen-rich gas.

Plasmatrons have traditionally been used to produce hydrogen-rich
gas for industrial applications like metallurgical processing.
They are usually quite large--about the size of a car engine--and
require large amounts of electrical power. "To our knowledge we're
the first to develop a plasma-boosted fuel reformer that's this
small and that operates at low power (less than one kilowatt),"
said Dr. Cohn.

CURRENT RESULTS

"The real achievement of the recent tests was our ability to run
our new plasmatron connected to an engine for long periods of
time," Dr. Rabinovich said. "We ran it reliably for four to six
hours a day over two weeks, with no traces of deterioration."

In addition, the researchers found that emissions of key
pollutants were significantly reduced. For example, NOx was
reduced from an average 2,700 parts per million without the
plasmatron to 20 ppm with the device.

"This is the first time anyone's been able to integrate a compact
plasma-boosted fuel reformer with an auto engine and show a large
reduction in pollutants," Dr. Cohn said. In an actual vehicle
these reductions will not be as dramatic (due to help from the
catalytic converter), but the researchers still expect to reduce
NOx emissions by a factor of 10.

The researchers believe that the plasmatron used in the current
tests has the basic features needed for commercial attractiveness.
For example, they estimate that the entire plasmatron system could
cost no more than two to three hundred dollars. Moreover, the only
component that may need to be replaced-an electrode-is very
inexpensive and can be changed as easily as a spark plug.

The next step in the work-placing the plasmatron in an actual
vehicle-will require integrating the system to the vehicle's
onboard computer. Dr. Rabinovich also notes that "the plasmatron
will require some additional room, but there's no need for a major
redesign of the vehicle." The team hopes to put the device in a
bus within a year.

VARIETY OF FUELS

The recent engine tests were conducted using gasoline. However,
laboratory tests with the plasmatron alone have shown that the
device can also process diesel and biocrude fuels.

Although in principle the device could process all of the fuel for
a vehicle, the researchers say that it's most cost-effective to
convert only a fraction of the fuel into hydrogen-rich gas. That's
because even though such gas increases the efficiency of an
engine, the plasmatron itself consumes energy. The best results in
the recent tests were achieved by converting 25 percent of the
gasoline into hydrogen-rich gas.

The plasmatron grew out of work conducted over 15 years ago by Dr.
Rabinovich, who was then an engineer in the former Soviet Union.
Dr. Alexeev, a colleague of Dr. Rabinovich's at the time, came to
MIT this year to join his friend on the team (he has since
returned to Russia). The plasmatron also owes a debt to basic
research at MIT on fusion power, which uses plasmas.

The researchers have five patents related to the plasmatron. The
work is supported by the DOE Office of Heavy Vehicle Technologies.

A plasmatron is a device that can convert gasoline and diesel fuel
into hydrogen. Hydrogen can be used in diesel engines to reduce
nitrogen oxides (NOx) emission.

The researchers and colleagues from industry report that the
plasmatron, used with an exhaust treatment catalyst on a diesel
engine bus, removed up to 90 percent of nitrogen oxides (NOx) from
the bus’s emissions. Nitrogen oxides are the primary components of
smog.

The plasmatron reformer also cut in half the amount of fuel needed
for the removal process. “The absorption catalyst approach under
consideration for diesel exhaust NOx removal requires additional
fuel to work,” explained Daniel R. Cohn, one of the leaders of the
team and head of the Plasma Technology Division at MIT's Plasma
Science and Fusion Center (PSFC). “The plasmatron reformer reduced
that amount of fuel by a factor of two compared to a system
without the plasmatron.”

In gasoline engines the use of plasmatrons will boost car fuel
efficiency by 20 percent.

"If widespread use of plasmatron hydrogen-enhanced gasoline
engines could eventually increase the average efficiency of cars
and other light-duty vehicles by 20 percent, the amount of
gasoline that could be saved would be around 25 billion gallons a
year," Cohn said. "That corresponds to around 70 percent of the
oil that is currently imported by the United States from the
Middle East."

The Bush administration has made development of a hydrogen-powered
vehicle a priority, Heywood noted. "That's an important goal, as
it could lead to more efficient, cleaner vehicles, but is it the
only way to get there? Engines using plasmatron reformer
technology could have a comparable impact, but in a much shorter
time frame," he said.

"Our objective is to have the plasmatron in production—and in
vehicles—by 2010," Smaling said. ArvinMeritor is working with a
vehicle concept specialist company to build a proof-of-concept
vehicle that incorporates the plasmatron in an internal combustion
engine. "We'd like to have a driving vehicle in one and a half
years to demonstrate the benefits," Smaling said.

In the meantime, the team continues to improve the base
technology. At the DEER meeting, Bromberg, for example, reported
cutting the plasmatron's consumption of electric power "by a
factor of two to three."

A plasmatron-catalyst system. The system generates hydrogen-rich
gas and comprises a plasmatron and at least one catalyst for
receiving an output from the plasmatron to produce hydrogen-rich
gas. In a preferred embodiment, the plasmatron receives as an
input air, fuel and water/steam for use in the reforming process.
The system increases the hydrogen yield and decreases the amount
of carbon monoxide.

Substantial progress in engine emission control is needed in order
to meet present and proposed regulations for both spark ignition
and diesel engines. Tightening regulations throughout the world
reflect the ongoing concern with vehicle emissions. Recently
developed compact plasmatron fuel converters have features that
are suitable for onboard production of hydrogen for both fuel
pretreatment and for exhaust aftertreatment applications. Systems
that make use of these devices in conjunction with aftertreatment
catalysts have the potential to improve significantly prospects
for reduction of diesel engine emissions. Plasmatron fuel
converters can provide a rapid response compact means to transform
efficiently a wide range of hydrocarbon fuels into hydrogen rich
gas. They have been used to reform natural gas [Bromberg1],
gasoline [Green], diesel [Bromberg2] and hard-to-reform biofuels
[Cohn1] into hydrogen rich gas (H2 + CO). The development of these
devices has been pursued for the purpose of reducing engine
exhaust pollutants by providing hydrogen rich gas for combustion
in spark ignition and possibly diesel engines, as shown in Figure
1 [Cohn2]. Recent developments in compact plasmatron reformer
design at MIT have resulted in substantial decreases in electrical
power requirements. These new developments also increase the
lifetime of the electrodes.

A novel apparatus and method is disclosed for a plasmatron fuel
converter ("plasmatron") that efficiently uses electrical energy
to produce hydrogen rich gas. The volume and shape of the plasma
discharge is controlled by a fluid flow established in a plasma
discharge volume. A plasmatron according to this invention
produces a substantially large effective plasma discharge volume
allowing for substantially greater volumetric efficiency in the
initiation of chemical reactions within a volume of bulk fluid
reactant flowing through the plasmatron.

A novel apparatus and method is disclosed for a plasmatron fuel
converter (""plasmatron"") that efficiently uses electrical energy
to produce hydrogen rich gas. The volume and shape of the plasma
discharge is controlled by a fluid flow established in a plasma
discharge volume. A plasmatron according to this invention
produces a substantially large effective plasma discharge volume
allowing for substantially greater volumetric efficiency in the
initiation of chemical reactions within a volume of bulk fluid
reactant flowing through the plasmatron.

A plasmatron fuel reformer has been developed for onboard hydrogen
generation for vehicular applications. These applications include
hydrogen addition to spark-ignition internal combustion engines,
NOx trap and diesel particulate filter (DPF) regeneration, and
emissions reduction from spark ignition internal combustion
engines First, a thermal plasmatron fuel reformer was developed.
This plasmatron used an electric arc with relatively high power to
reform fuels such as gasoline, diesel and biofuels at an oxygen to
carbon ratio close to 1. The draw back of this device was that it
has a high electric consumption and limited electrode lifetime due
to the high temperature electric arc. A second generation
plasmatron fuel reformer was developed. It used a low-current
high-voltage electric discharge with a completely new electrode
continuation. This design uses two cylindrical electrodes with a
rotating discharge that produced low temperature volumetric cold
plasma., The lifetime of the electrodes was no longer an issue and
the device was tested on several fuels such as gasoline, diesel,
and biofuels at different flow rates and different oxygen to
carbon ratios. Hydrogen concentration and yields were measured for
both the thermal and non-thermal plasmatron reformers for
homogeneous (non-catalytic) and catalytic reforming of several
fuels. The technology was licensed to an industrial auto part
supplier (ArvinMeritor) and is being implemented for some of the
applications listed above. The Plasmatron reformer has been
successfully tested on a bus for NOx trap regeneration. The
successful development of the plasmatron reformer and its
implementation in commercial applications including transportation
will bring several benefits to the nation. These benefits include
the reduction of NOx emissions, improving engine efficiency and
reducing the nation's oil consumption. The objective of this
program has been to develop attractive applications of plasmatron
fuel reformer

A reduced toxicity fuel satellite propulsion system including a
reduced toxicity propellant supply for consumption in an axial
class thruster and an ACS class thruster. The system includes
suitable valves and conduits for supplying the reduced toxicity
propellant to the ACS decomposing element of an ACS thruster. The
ACS decomposing element is operative to decompose the reduced
toxicity propellant into hot propulsive gases. In addition the
system includes suitable valves and conduits for supplying the
reduced toxicity propellant to an axial decomposing element of the
axial thruster. The axial decomposing element is operative to
decompose the reduced toxicity propellant into hot gases. The
system further includes suitable valves and conduits for supplying
a second propellant to a combustion chamber of the axial thruster.
whereby the hot gases and the second propellant auto-ignite and
begin the combustion process for producing thrust.

Today's form of jet engine power comes from what is called a gas
turbine engine. This engine is on average 14% efficient and emits
great quantities of green house gas carbon dioxide and air
pollutants, Le. nitrogen oxides and sulfur oxides. The alternate
method being researched involves a reformer and a solid oxide fuel
cell (SOFC). Reformers are becoming a popular area of research
within the industry scale. NASA Glenn Research Center's approach
is based on modifying the large aspects of industry reforming
processes into a smaller jet fuel reformer. This process must not
only be scaled down in size, but also decrease in weight and
increase in efficiency. In comparison to today's method, the Jet A
fuel reformer will be more efficient as well as reduce the amount
of air pollutants discharged. The intent is to develop a 10kW
process that can be used to satisfy the needs of commercial jet
engines. Presently, commercial jets use Jet-A fuel, which is a
kerosene based hydrocarbon fuel. Hydrocarbon fuels cannot be
directly fed into a SOFC for the reason that the high temperature
causes it to decompose into solid carbon and Hz. A reforming
process converts fuel into hydrogen and supplies it to a fuel cell
for power, as well as eliminating sulfur compounds. The SOFC
produces electricity by converting H2 and CO2. The reformer
contains a catalyst which is used to speed up the reaction rate
and overall conversion. An outside company will perform a catalyst
screening with our baseline Jet-A fuel to determine the most
durable catalyst for this application. Our project team is
focusing on the overall research of the reforming process.
Eventually we will do a component evaluation on the different
reformer designs and catalysts. The current status of the project
is the completion of buildup in the test rig and check outs on all
equipment and electronic signals to our data system. The objective
is to test various reformer designs and catalysts in our test rig
to determine the most

At Argonne National Laboratory we are developing a process to
convert hydrocarbon fuels to a clean hydrogen feed for a fuel
cell. The process incorporates a partial oxidation/steam reforming
catalyst that can process hydrocarbon feeds at lower temperatures
than existing commercial catalysts. We have tested the catalyst
with three diesel-type fuels: hexadecane, low-sulfur diesel fuel,
and a regular diesel fuel. We achieved complete conversion of the
feed to products. Hexadecane yielded products containing 60%
hydrogen on a dry, nitrogen-free basis at 800 C. For the two
diesel fuels, higher temperatures, >850 C, were required to
approach similar levels of hydrogen in the product stream. At 800
C, hydrogen yield of the low sulfur diesel was 32%, while that of
the regular diesel was 52%. Residual products in both cases
included CO, CO{sub 2}, ethane, ethylene, and methane.

Argonne National Laboratory is developing a process to convert
hydrocarbon fuels to clean hydrogen feeds for a polymer
electrolyte fuel cell. The process incorporates an autothermal
reforming catalyst that can process hydrocarbon feeds at lower
temperatures than existing commercial catalysts. The authors have
tested the catalyst with three diesel-type fuels: hexadecane,
certified low-sulfur grade 1 diesel, and a standard grade 2
diesel. Hexadecane yielded products containing 60% hydrogen on a
dry, nitrogen-free basis at 850 C, while maximum hydrogen product
yields for the two diesel fuels were near 50%. Residual products
in all cases included CO, CO{sub 2}, ethane, and methane. Further
studies with grade 1 diesel showed improved conversion as the
water:fuel ratio was increased from 1 to 2 at 850 C. Soot
formation was reduced when the oxygen:carbon ratio was maintained
at 1 at 850 C. There were no significant changes in hydrogen yield
as the space velocity and the oxygen:fuel ratio were varied. Tests
with a microchannel monolithic catalyst yielded similar or
improved hydrogen levels at higher space velocities than with
extruded pellets in a packed bed.

A reformer is disclosed that includes a plasma zone to receive a
pre-heated mixture of reactants and ionize the reactants by
applying an electrical potential thereto. A first thermally
conductive surface surrounds the plasma zone and is configured to
transfer heat from an external heat source into the plasma zone.
The reformer further includes a reaction zone to chemically
transform the ionized reactants into synthesis gas comprising
hydrogen and carbon monoxide. A second thermally conductive
surface surrounds the reaction zone and is configured to transfer
heat from the external heat source into the reaction zone. The
first thermally conductive surface and second thermally conductive
surface are both directly exposed to the external heat source. A
corresponding method and system are also disclosed and claimed
herein.

In this study, a plasmatron reactor was used for gasifying the
waste of distillers grains at different temperatures (773, 873,
973 K) and water flow rates (1, 2, 3 mL min(-1)), which were
heated to produce steam. Among all the gas products, syngas was
the major component (88.5 wt.% or 94.66 vol.%) with temperatures
yielding maximum concentrations at 873 K with a relatively high
reaction rate. The maximum concentrations regarding gaseous
production occurring times are all below 1 min. With the increase
of steam, the recovery mass yield of syngas also increases from
34.14 to 45.47 approximately 54.66 wt.% at 873 K. Water-gas
reactions and steam-methane reforming reactions advance the
production of syngas with the increase of steam. Furthermore, the
water-shift reaction also increases in the context of steam
gasification which leads to the decrease of CO(2) at the same
time. PMID:20163957

Depending on the market, refiner`s plans to produce clean fuels
and higher value petrochemicals will weigh heavily on the
catalytic reformer`s flexibility. It seems that as soon as a
timely article related to catalytic reforming operations is
published, a new {open_quotes}boutique{close_quotes} gasoline fuel
specification is slapped on to existing fuel standards, affecting
reformer operations and processing objectives. Just as
importantly, the petrochemical market (such as aromatics) that
refiners are targeting, can be very fickle. That`s why process
engineers have endeavored to maintain an awareness of the
flexibility that technology suppliers are building into modern
catalytic reformers.

In this paper a control system for autothermal reforming reactor
for diesel fuel is presented. Autothermal reforming reactors and
the pertaining purification reactors are used to convert diesel
fuel into hydrogen-rich reformate gas, which is then converted
into electricity by the fuel cell. The purpose of the presented
control system is to control the hydrogen production rate and the
temperature of the autothermal reforming reactor. The system is
designed in such a way that the two control loops do not interact,
which is required for stable operation of the fuel cell. The
presented control system is a part of the complete control system
of the diesel fuel cell auxiliary power unit (APU).

An apparatus for reforming fuel oil wherein ultrasonic waves are
utilized. The apparatus comprises a closed vessel, a rotary
collector formed in a cylindrical shape, an inlet conduit for
supplying fuel oil to be reformed into the vessel, an outlet
conduit for delivering reformed oil from the vessel, and a
ultrasonic irradiating device. The rotary collector has a layered
mesh structure of a fine mesh, preferably of mesh size between 2
mu M and 20 mu m, mounted thereon so that sludge contained in the
fuel oil to be reformed is collected on the layered mesh
structure. One end of a horn connected to the ultrasonic wave
irradiating device faces the layered mesh structure forming a
small gap therebetween so that the sludge collected on the layered
mesh structure is dissociated by the ultrasonic waves.

The problems of the prior art are overcome by the apparatus and
method disclosed herein. The reactor vessel of a plasma gasifier
is operated at high pressure. To compensate for the negative
effects of high pressure, various modifications to the plasma
gasifier are disclosed. For example, by moving the slag, more
material is exposed to the plasma, allowing better and more
complete processing thereof. In some embodiments, magnetic fields
are used to cause movement of the slag and molten metal within the
vessel. An additional embodiment is to add microwave heating of
the slag and/or the incoming material. Microwave heating can also
be used as an alternative to plasma heating in a high pressure
gasification system.

Methods and apparatus for high efficiency generation of
electricity and low oxides of nitrogen (NOx) emissions are
provided. The electricity is generated from combustion of
hydrogen-rich gases produced in waste conversion units using ultra
lean fuel to air ratios in the range of 0.4-0.7 relative to
stoichiometric operation in internal combustion engine-generators
or ultra lean operation in gas turbines to ensure minimal
production of pollutants such as NOx. The ultra lean operation
also increases the efficiency of the internal combustion engine.
High compression ratios (r=12 to 15) can also be employed to
further increase the efficiency of the internal combustion engine.
Supplemental fuel, such as natural gas or diesel oil, may be added
directly to the internal combustion engine-generator or gas
turbine for combustion with the hydrogen-rich gases produced in
waste conversion unit. In addition, supplemental fuel may be
reformed into a hydrogen-rich gas in a plasma fuel converter and
then introduced into the internal combustion engine-generator or a
gas turbine for combustion along with supplemental fuel and the
hydrogen-rich gases produced in waste conversion unit. The
preferred embodiment of the waste conversion unit is a fully
integrated tunable arc plasma-joule heated melter with a common
molten pool and power supply circuits which can be operated
simultaneously without detrimental interaction with one another.
In this embodiment, the joule heated melter is capable of
maintaining the material in a molten state with sufficient
electrical conductivity to allow rapid restart of a transferred
arc plasma.

US5847353 Methods and apparatus for low NOx emissions during the
production of electricity from waste treatment systems

Methods and apparatus for high efficiency generation of
electricity and low oxides of nitrogen (NOx) emissions are
provided. The electricity is generated from combustion of
hydrogen-rich gases produced in waste conversion units using ultra
lean fuel to air ratios in the range of 0.4-0.7 relative to
stoichiometric operation in internal combustion engine-generators
or ultra lean operation in gas turbines to ensure minimal
production of pollutants such as NOx. The ultra lean operation
also increases the efficiency of the internal combustion engine.
High compression ratios (r=12 to 15) can also be employed to
further increase the efficiency of the internal combustion engine.
Supplemental fuel, such as natural gas or diesel oil, may be added
directly to the internal combustion engine-generator or gas
turbine for combustion with the hydrogen-rich gases produced in
waste conversion unit. In addition, supplemental fuel may be
reformed into a hydrogen-rich gas in a plasma fuel converter and
then introduced into the internal combustion engine-generator or a
gas turbine for combustion along with supplemental fuel and the
hydrogen-rich gases produced in waste conversion unit. The
preferred embodiment of the waste conversion unit is a fully
integrated tunable arc plasma-joule heated melter with a common
molten pool and power supply circuits which can be operated
simultaneously without detrimental interaction with one another.
In this embodiment, the joule heated melter is capable of
maintaining the material in a molten state with sufficient
electrical conductivity to allow rapid restart of a transferred
arc plasma.

Systems for producing hydrogen-rich gases including rapid response
plasma fuel converters are provided. The rapid response plasma
fuel converters systems are suitable for use in vehicles and the
like in which the systems are capable of instantaneously providing
hydrogen-rich gas, reducing pollutants during vehicle startup and
allowing use of hydrogen-rich gas during load changes. The systems
are preferably capable of responding on the order of a second or
less. The systems include a plasma fuel converter for receiving
hydrocarbon fuel and reforming the hydrocarbon fuel into a
hydrogen-rich gas, an internal combustion engine adapted to
receive the hydrogen-rich gas from the plasma fuel converter, a
generator powered by the engine and connected to deliver
electrical energy to power the plasma fuel converter, and a power
supply circuit capable of rapidly providing power to the plasma
fuel converter in response to a stimulus. The stimulus can be
movement in the accelerator pedal controlled by the driver of the
vehicle. The plasma fuel converters can be operated pulsed or
non-pulsed modes of operation and can utilize arc or high
frequency discharges. The plasma fuel converter can be either
separated from the engine or directly integrated into the engine
to allow for more efficient use of the thermal energy produced by
the plasma fuel converter.

Systems for producing hydrogen-rich gases including rapid response
plasma fuel converters are provided. The rapid response plasma
fuel converters systems are suitable for use in vehicles and the
like in which the systems are capable of instantaneously providing
hydrogen-rich gas, reducing pollutants during vehicle startup and
allowing use of hydrogen-rich gas during load changes. The systems
are preferably capable of responding on the order of a second or
less. The systems include a plasma fuel converter for receiving
hydrocarbon fuel and reforming the hydrocarbon fuel into a
hydrogen-rich gas, an internal combustion engine adapted to
receive the hydrogen-rich gas from the plasma fuel converter, a
generator powered by the engine and connected to deliver
electrical energy to power the plasma fuel converter, and a power
supply circuit capable of rapidly providing power to the plasma
fuel converter in response to a stimulus. The stimulus can be
movement in the accelerator pedal controlled by the driver of the
vehicle. The plasma fuel converters can be operated pulsed or
non-pulsed modes of operation and can utilize arc or high
frequency discharges. The plasma fuel converter can be either
separated from the engine or directly integrated into the engine
to allow for more efficient use of the thermal energy produced by
the plasma fuel converter.

The plasma fuel converter includes an electrically conductive
structure for forming a first electrode and a second electrode is
disposed to create a gap with respect to the first electrode in a
reaction chamber. A fuel-air mixture is introduced into the gap
and the power supply is connected to the first and second
electrodes to provide voltage in the range of approximately 100
volts to 40 kilovolts and current in the range of approximately 10
milliamperes to 1 ampere to generate a glow discharge to reform
the fuel. The high voltage low current plasmatron of the invention
is low cost, has long electrode life, utilizes a simple power
supply and control and eliminates the need for an air compressor.

The present invention provides a relatively compact and highly
robust waste-to-energy conversion system and apparatus which has
the advantage of complete or substantially complete conversion of
a wide range of waste streams into useful gas and a stable,
nonleachable solid product at a single location with greatly
reduced air pollution to meet air quality standards. The gas may
be utilized in a combustion process to generate electricity and
the solid product can be suitable for various commercial
applications. Alternatively, the solid product stream, which is a
safe, stable material, may be disposed of without special
considerations as hazardous material. In one embodiment of the
invention, the conversion system includes an arc plasma furnace
directly coupled to a joule heated melter. In an alternative and
preferred embodiment of the invention, the arc plasma furnace and
joule heated melter are formed as a completely integrated unit
having circuit arrangements for the simultaneous operation of both
the arc plasma and the joule heated portions of the unit without
interference with one another. The apparatus may additionally be
employed without further use of the gases generated by the
conversion process.

The system includes a source of emissions and a catalyst for
receiving the emissions. Suitable catalysts are absorber catalysts
and selective catalytic reduction catalysts. A plasma fuel
converter generates a reducing gas from a fuel source and is
connected to deliver the reducing gas into contact with the
absorber catalyst for regenerating the catalyst. A preferred
reducing gas is a hydrogen rich gas and a preferred plasma fuel
converter is a plasmatron. It is also preferred that the absorber
catalyst be adapted for absorbing NOx.

A novel apparatus and method is disclosed for a plasmatron fuel
converter ("plasmatron") that efficiently uses electrical energy
to produce hydrogen rich gas. The volume and shape of the plasma
discharge is controlled by a fluid flow established in a plasma
discharge volume. A plasmatron according to this invention
produces a substantially large effective plasma discharge volume
allowing for substantially greater volumetric efficiency in the
initiation of chemical reactions within a volume of bulk fluid
reactant flowing through the plasmatron.

The plasma fuel converter includes an electrically conductive
structure for forming a first electrode and a second electrode is
disposed to create a gap with respect to the first electrode in a
reaction chamber. A fuel-air mixture is introduced into the gap
and the power supply is connected to the first and second
electrodes to provide voltage in the range of approximately 100
volts to 40 kilovolts and current in the range of approximately 10
milliamperes to 1 ampere to generate a glow discharge to reform
the fuel. The high voltage low current plasmatron of the invention
is low cost, has long electrode life, utilizes a simple power
supply and control and eliminates the need for an air compressor.